1. Field of the Invention
The present invention relates to accessories for use with a portable seam welding gun that is used to seal seams between adjacent sheets of flooring, and the combination of these accessories with such a portable seam welding gun.
2. Description of the Prior Art
In laying flooring that is sold commercially in sheets, such as linoleum flooring, adjacent sheets of flooring are positioned side by side and cut to the desired shape. In the past the flooring sheets have been secured to the floor by adhesive compound. To secure the flooring sheets the compound is applied to the floor and the cut sheets of flooring are laid in position, one by one. Once each sheet of flooring is laid, the next adjacent flooring sheet is brought into position and pressed against the floor with the linear edges of adjacent flooring sheets residing in mutual abutment.
One major problem with laying sheets of flooring in this manner is that the adhesive bond between the underside of the flooring sheets and the subfloor therebeneath is sometimes inadequate. Quite often areas of the sheets of the flooring will tend to separate from the subfloor when the adhesive bond between the subfloor and the flooring sheets deteriorates due to age, movement of the subfloor, or improper installation.
The separation of areas of flooring sheets from the subfloor is particularly pronounced at the interfaces between adjacent sheets of flooring. The edges of adjacent flooring sheets which are supposed to reside in firm, mutual abutment, will sometimes tend to rise slightly from the subfloor. This presents both an unsightly appearance and also leads to a significant deterioration of the floor because of the separation that occurs when the edges of adjacent sheets of flooring rise. When separation between adjacent sheets of flooring occurs in this way, moisture, dirt and debris often find their way into the crack that forms between the flooring sheets, thus leading to further deterioration of the floor.
In the floor installation trade the use of fusible plastics to form a seal between the abutting edges of adjacent sheets of flooring has gained increased popular acceptance. According to this technique the edges of sheets of flooring are not cut perpendicular to the plane of the expanse of the flooring as has historically been the practice. Rather, the edges of the flooring are cut so that adjacent sheets of flooring, when moved into abutting relationship, define an upwardly facing, elongated groove where they meet. That is, the sheets of flooring are cut so that the exposed upper surface covers a slightly smaller area than the concealed undersurface, thus providing adjacent surfaces forming a groove or channel between adjoining sheets of flooring. These adjacent surfaces can be bonded together using a fusible thermoplastic applied from above. The color of the thermoplastic is chosen to match the color of the flooring so as to render the demarcation between adjacent sheets of flooring largely undetectable.
Large, relatively bulky, automated machines have been developed for applying a fusible plastic sealant to seams between adjacent sheets of flooring. Such automated machines roll upon the floor and apply a bead of molten thermoplastic along the seam between adjacent sheets of flooring. The heat required is provided by electrical resistance heating. The molten thermoplastic quickly cools and bonds to the adjoining edges of adjacent sheets of flooring. Once the adjoining edges of sheets of flooring have been sealed in this manner, they will not separate from each other, even in the event that the bond between the undersides of the sheets of flooring and the subfloor deteriorates with time. This prevents a noticeable gap from forming between adjacent sheets of flooring.
While automated seam sealing machines of the type described perform quite adequately for creating firm, durable sealed seams between adjacent sections of sheet flooring, their cost is well beyond the resources of the average sheet flooring installer. Therefore, a much more economical type of machine for creating a seam of fused thermoplastic between adjacent sheets of flooring was developed. Specifically, portable, hand-held seam welding guns have been available commercially for quite some time. Such hand-held guns are sold at only a fraction of the cost of automated seam welding machines and are also typically electrically powered and melt a thermoplastic bead by means of resistance heating.
Hand-held seam welding guns of this type are typically configured with a generally cylindrical body forming the rear portion of the gun and a heat conducting member projecting forwardly from the body along a longitudinal axis. A heat concentration nose, typically formed of a highly conductive metal, such as copper or a copper alloy, is mounted on the heat conducting member and includes a heating tip mounting post. The heating tip mounting post projects forwardly along the longitudinal axis of the body and may be of a narrow, tubular configuration. The heating tip mounting post accommodates a hollow heating tip.
A conventional, portable, hand-held seam welding gun heating tip includes a hollow cylindrical sleeve that fits onto the heating tip mounting post and another tubular structure that accommodates an elongated length of thermoplastic that is fed into the tip and melted therein. Conventional, hand-held seam welding guns of this type are manufactured in Europe and sold under the brand names Leister and Zinser. Both of these types of hand-held seam welding guns are sold commercially by Janser, Inc., located at 200 Paw Paw Avenue, Benton Harbor, Mich. 49022-3400.
While conventional, hand-held, portable seam welding guns of the type described can produce high quality seams, it is extremely difficult to manually manipulate these devices to consistently achieve a high quality seam. Because the hand-held, portable seam welding guns are relatively small in size, they must be held by the installer at just the right orientation relative to the floor in order for the thermoplastic welding rods to melt and flow properly into the elongated groves formed between adjacent sheets of flooring and to properly bond to the adjacent edges of the mutually abutting sheets of flooring to establish a secure, permanently sealed seam. If the hand-held seam sealing guns are held at too great or too small an angle relative to the floor, the thermoplastic welding rods will not flow properly into the channel defined between the adjacent sheets of flooring as they melt, or will not bond properly to both of the adjacent edges of adjoining flooring sheets.
Likewise, if portable, hand-held seam sealing guns of this type are tilted even slightly to one side or the other, bonding to the adjoining edges of the flooring sheets is likely to be inconsistent. Thus, the proper operation of such hand-held seam sealing guns requires intense concentration and allows virtually no margin of error. The seams produced by these devices are therefore quite likely to be defective.
Furthermore, the physical configuration of the parts of conventional, hand-held seam sealing guns is such that the flooring installer in unable to visually see whether or not the molten plastic substance is being extruded at the proper angle relative to the floor. The necessary visual observation in this regard can only be performed if the installer kneels far forward and positions his head quite close to the floor while operating the device. This is an extremely tedious and tiring process. Furthermore, with the great fatigue which the installer typically experiences from remaining in this position, mistakes in orientation of the welding gun, and hence defective seams between sheets of flooring, become more and more likely.